Guides & how-tos
Free, practical how-to guides for working with video, images, PDFs, data and more — each one links to the browser-based tool that does the job.
- How to calculate video file size from bitrate and duration — The one formula that links file size, bitrate and duration — and how to solve for any of the three.
- What bitrate should you use for 1080p and 4K video? — Sensible export bitrates by resolution and frame rate, and why HEVC/AV1 need far less than H.264.
- How to scale a resolution by percentage (without half-pixels) — Scale a resolution by a percentage while keeping the ratio — and pick scales that stay on even pixels.
- How to make a vCard QR code to share your contact — Turn your contact details into a .vcf file and a scannable QR anyone can point a camera at.
- How Do You Calculate a Subnet from a CIDR Block? — Turn any CIDR notation into network, broadcast, mask and usable host range without command-line math.
- How Do I Convert an IP Address to Decimal, Binary, or Hex? — Turn any IPv4 into its decimal, hex, binary and octal forms and expand or compress IPv6 addresses without leaving your browser.
- How Do You Generate a Random MAC Address and Look Up Its Vendor? — Make safe test MAC addresses and decode vendor, format, and flags - all locally in your browser.
- How to Use a Scientific Calculator Online — Type a full math expression, see the answer live, and switch between degrees and radians, all in your browser with nothing uploaded.
- How Do You Convert Numbers to Roman Numerals? — A plain-English guide to converting between numbers and Roman numerals, with the rules, the symbols, and a free in-browser converter.
- How Do You Validate an IBAN? A Free, Private Checker — Check an IBAN's structure and checksum instantly in your browser — no account number ever leaves your device.
- How Do I Make a CSS Gradient? — Build linear, radial, and conic CSS gradients visually, then copy the code in seconds.
- How Do I Create a Custom CSS Easing Curve with cubic-bezier()? — Drag two handles, watch a live preview, and copy a cubic-bezier() value that makes your CSS animations feel natural instead of robotic.
- How Do I Create a CSS Clip-Path Shape Without Writing Coordinates? — Pick a shape, tune it with a slider, and copy cross-browser clip-path CSS - no coordinate math required.
- How Do I Make a Pure-CSS Loading Spinner? — Pick a style, tune size, color and speed, and copy a paste-ready pure-CSS spinner snippet.
- How do I resize an image online without uploading it? — Resize, crop and rotate images to exact sizes right in your browser — no upload, no install.
- How Do I Make a Meme With My Own Picture? — Caption any photo with classic top-and-bottom meme text and download a clean PNG — no upload, no watermark, no account.
- How Do You Generate an HMAC Online? — Sign a message with a secret key and get the HMAC in hex or Base64 — computed locally in your browser.
- How Do I Generate an RSA or EC Key Pair in the Browser? — Create RSA and elliptic-curve key pairs as PEM locally, with the private key never leaving your browser.
- How do I zip and unzip files online without uploading them? — Bundle files into a .zip or open one to preview and download entries, entirely in your browser.
- How to Separate PDF Pages — Every way to separate a PDF — extract specific pages, split into individual files, split in half, remove pages, and grab odd or even pages — done free and privately in your browser, with nothing uploaded.
- How to Split a PDF Into Multiple Files — Turn one PDF into many separate files, downloaded together as a zip, entirely in your browser. Three fast methods: extract each page separately, split every N pages, or split evenly into a chosen number of files.
- How to Split a PDF in Half (or Into Any Number of Equal Files) — Split any PDF in half — or into thirds, quarters, or any number of equal files — in seconds, entirely in your browser with nothing uploaded. Here is the exact step-by-step method, with worked examples.
- How to Extract Specific Pages from a PDF — Pull out just the pages you need — a single page or a range like 5-8 — into a new PDF, using thumbnail select or page ranges, entirely in your browser.
- How to Delete or Remove Pages from a PDF — Remove blank pages, an appendix, or any pages you don't want and keep the rest as a single clean PDF — free, private, and entirely in your browser.
- How to Extract All Odd or Even Pages From a PDF — Use the Odd/Even quick-select to pull all fronts or all backs out of a PDF — the standard fix for double-sided scans from a single-sided scanner. Free, private, in-browser.
- How to Compress a Video Without Losing Quality — Shrink an MP4 to a target size or quality preset entirely in your browser — no upload, no watermark, no signup.
- How to Extract Audio from a Video (Video to MP3) — Pull the soundtrack out of any video as MP3, WAV, FLAC or OGG — entirely on your device, no upload.
- How to Make a Video Vertical for TikTok & Shorts — Turn landscape footage into 9:16 for TikTok, Reels & Shorts — crop or blur-pad, with platform safe zones, all on-device.
- How to Add Subtitles to a Video (Free, No Upload) — Burn styled captions into any video — from an SRT/VTT file or on-device AI auto-captions. Private, free, no watermark.
- How to Convert MOV to MP4 (Free, In Your Browser) — Turn a MOV into an MP4 in your browser — usually an instant lossless remux, never an upload.
- How to Remove Silence from Audio Automatically — Auto-detect and cut dead air (and ums/uhs) from a recording on your device — preview each cut, export clean audio.
- How to Convert an Image to ASCII Art — Upload a photo, tune the character density, and copy or download the ASCII art — all in your browser.
- How to Remove the Background From a Photo — Cut out a subject and get a clean transparent PNG — no account, no upload, runs in your browser.
- How to Make a Barcode (Free, No Upload) — Type a value, pick the symbology, and download a print-ready PNG or SVG barcode — all in your browser.
- How to Convert Decimal to Binary, Hex & Octal — Convert between decimal, binary, hex and octal — the remainder method by hand, plus an instant browser tool.
- How to Encode and Decode Base64 Online — Encode text and files to Base64 or decode it back, with URL-safe and data URI support — all in your browser.
- How to Make a Business Card With a QR Code — Design a print-ready business card with a scannable contact QR code, free and entirely in your browser.
- How to Calculate Monthly Loan Payments — Turn loan amount, interest rate, and term into an exact monthly payment and amortization schedule.
- How to Decode an SSL Certificate or CSR — Read the subject, issuer, SANs, and validity dates inside any X.509 certificate or CSR — locally, no upload.
- How to Add Chapters to a YouTube Video — Build a valid YouTube chapters block that passes the 0:00, 3-chapter, and 10-second rules — in your browser.
- What does chmod 755 mean? Octal vs rwx explained — Decode chmod 755, 644, 777 and any Unix permission — what each octal digit and rwx letter really means.
- How to Beautify and Minify Code Online — Format messy code or shrink it for production — HTML, CSS, and JS, all in one panel, right in your browser.
- How to Check a Design for Color Blindness — Preview your UI through protanopia, deuteranopia, and tritanopia to catch color-only cues before users do.
- How to convert HEX to RGB (and HSL, OKLCH) — Paste any HEX, RGB, HSL or OKLCH color and get every other format plus a live WCAG contrast score.
- How to Write a Cron Expression (With Examples) — The 5 cron fields explained, copy-paste examples, and how to check the next run times before you ship.
- How to Convert CSV to JSON (Free, In Your Browser) — Paste or drop a CSV, preview it as a typed table, and copy clean JSON — all locally in your browser.
- How to Convert a cURL Command to JavaScript fetch() — Turn a curl command into a clean JavaScript fetch() call — how the flags map over, with a free in-browser converter.
- How to Convert YAML to JSON (and Back) in Your Browser — Turn YAML into JSON (or TOML) in seconds — paste, pick the formats, copy the result. All local, no upload.
- How to Extract Emails and Data from Text — Pull every email, URL, phone number, date and dollar amount out of messy text into structured JSON — offline.
- How to Transcribe Audio to Text (Free, In Your Browser) — Turn an MP3, a meeting, or your own speech into accurate text — locally, with no upload and no signup.
- How to Convert a Word DOCX to Markdown (or HTML) — Turn a Word .docx into clean Markdown, HTML or plain text in seconds — entirely in your browser.
- How to password-protect a file with AES-256 — Lock a file or message behind a passphrase with AES-256-GCM — fully in your browser, nothing uploaded.
- How to Convert a .env File to JSON (and Back) — Turn KEY=VALUE config into a flat JSON object — and JSON back into .env lines — right in your browser.
- How to Convert Epoch Time to a Date — Turn a 10- or 13-digit Unix timestamp into a readable date (and back) in seconds, ms, or any timezone.
- How to Open an XLSX File Without Excel — View any spreadsheet and convert it to JSON or CSV in your browser — no Excel, no signup, no upload.
- How to Remove EXIF Data From Photos — See the hidden metadata in your photos — including GPS location — and strip it before you share.
- How to Make Fancy Text for Bios and Titles — Turn plain words into bold, italic, or script Unicode styles you can paste anywhere — no app, no signup.
- How to Create a Favicon From an Image (Full Set) — Turn one image into favicon.ico, Apple touch, and PWA icons — plus the exact HTML link tags to paste.
- How to Check a File's Real Type (Not the Extension) — Find a file's real type from its magic bytes — not its (possibly fake) extension — and read it in hex.
- How to Make Flashcards Online (Free, No Signup) — Type your cards, study them with spaced repetition, quiz yourself, and export to Anki — no account needed.
- How to center a div with Flexbox (and CSS Grid) — Two reliable ways to perfectly center any element — plus how to grab the CSS or Tailwind without guessing.
- How to validate YAML frontmatter before you build — Catch missing keys, wrong types, broken slugs and bad meta lengths before your static site build fails.
- How to Make a GIF From a Video (Free, In Browser) — Trim a clip, set the frame rate and size, add a caption, and export an animated GIF — all in your browser.
- How to Create a .gitignore File (Fast Templates) — Pick your stack, merge clean templates, and get a ready-to-use .gitignore — no duplicate rules, nothing uploaded.
- How to Create a Glassmorphism Effect in CSS — The frosted-glass look in CSS comes down to four properties — here's the recipe and a live generator.
- How to verify a file checksum (MD5, SHA-256) — Confirm a downloaded file wasn't corrupted or tampered with by matching its hash to the published checksum.
- How to Convert HEIC to JPG (Free, No Upload) — Turn iPhone HEIC photos into JPG or PNG right in your browser — batch convert up to 100 at once, nothing uploaded.
- How to Encode and Decode HTML Entities — Turn &, <, > and Unicode symbols into safe HTML entities (and back) — and when you actually need to.
- How to create an .ics calendar file (free) — Build a downloadable .ics calendar invite with recurrence and reminders, right in your browser.
- How to make a passport photo at home for free — Turn a phone selfie into a properly sized passport or profile photo — clean background, right crop, no upload.
- How to Compress an Image Without Losing Quality — Shrink JPEG and PNG files dramatically while keeping them sharp — format, quality, and resize, done in your browser.
- How to Blur Faces in a Photo (Free, In-Browser) — Hide faces, plates and personal details in a photo with blur, pixelate or black-out — all in your browser.
- How to Convert Images to PDF (Free, In-Browser) — Combine JPG, PNG, and WebP photos into one PDF with control over page size, margins, and order.
- How to Make an Invoice (Free, in Your Browser) — The fields a proper invoice needs, how to total it correctly, and how to export a clean PDF in minutes.
- How to filter and query JSON with jq — Pull values, filter arrays and reshape JSON with jq — the core filters explained, with a live playground.
- How to Compare Two JSON Files and See What Changed — Paste two JSON documents and get a key-aware diff of every added, removed, and changed value.
- How to Fix Invalid JSON (Auto-Repair in Browser) — Auto-repair broken JSON — trailing commas, single quotes, comments — then mask secrets or convert to YAML/CSV.
- How to Generate a JSON Schema From Sample JSON — Turn a sample JSON payload into a draft-07 schema, then validate real data against it in seconds.
- How to Generate TypeScript Types From JSON — Turn a JSON sample into TypeScript interfaces or Go, Rust, Python, and Swift types in seconds — all in your browser.
- How to decode a JWT token (safely, offline) — Read a JWT's header and claims, check exp/nbf, and verify the signature — without sending the token to any server.
- How to Transcribe Speech in Real Time, Free — Get a live, on-screen transcript of speech as it happens — entirely in your browser, with nothing uploaded.
- How to Convert Markdown to PDF (and HTML) — Paste Markdown, preview it live, and export a printable PDF or clean HTML file — all in your browser.
- How to Make a Markdown Table (the Easy Way) — Build a clean Markdown table in seconds — type the syntax by hand or edit it like a spreadsheet.
- How to Make a Seamless Audio Loop From a Clip — Trim a clip to a clean, repeating loop in your browser — set the points, preview, export a WAV.
- How to Add Meta Tags to Your Website — Generate title, description, Open Graph and Twitter card tags plus a robots.txt — with live SERP and social previews.
- How to Tune a Guitar Online (Free Browser Tuner) — Match each string to the right note and cents using a free, private browser tuner — no app, no signup.
- How to Generate Fake Data for Testing — Build realistic JSON, CSV, or SQL test fixtures from custom columns — no signup, nothing uploaded.
- How to Convert Natural Language to SQL — Turn a plain-English question into a working SQL query — with your schema kept private, on-device.
- How to Extract Text From an Image (Free, In-Browser) — Turn a photo, screenshot, or scanned PDF into selectable, editable text — entirely on your device.
- How to Remove Metadata from a Word Document — Strip author, company and revision data from Office files before you share them — privately, in your browser.
- How to Extract a Color Palette From an Image — Pull the dominant colors out of any photo as hex swatches and preview them on a real UI mockup.
- How to Create a Strong Password (or Passphrase) — What actually makes a password hard to crack — length, randomness, entropy — and how to generate one safely.
- How to Check If Your Password Is Strong (Free) — Score any password and see how long it would take to crack — all locally, no uploads.
- How to Compare Two PDFs and See What Changed — Spot every changed word between two PDF versions with a side-by-side redline diff — privately, in your browser.
- How to Reduce PDF File Size Without Uploading It — Shrink a bloated PDF for email or upload limits — recompressed locally, with nothing sent to a server.
- How to Fill Out a PDF Form and Sign It (Free) — Fill PDF form fields, check boxes, and drop a drawn signature — all locally in your browser, free.
- How to merge PDF files (free, in your browser) — Combine several PDFs into one, then reorder, rotate and delete pages — all locally, nothing uploaded.
- How to Split a PDF Into Separate Pages or Files — Extract a range, pull single pages, or chunk a PDF — all locally in your browser, nothing uploaded.
- How to Add a Watermark to a PDF (Free, In Browser) — Stamp a diagonal watermark and page numbers onto any PDF locally — nothing uploaded, no account.
- How to Convert a PDF to Images (PNG, JPG, WebP) — Turn every PDF page into a sharp PNG, JPG or WebP at the resolution you choose — locally, no upload.
- How to Remove Restrictions From a PDF (Print, Copy, Edit) — Strip the no-print, no-copy and no-edit locks from a PDF you can open — locally, no upload, no signup.
- How to Redact PII From Text Before Sharing — Mask emails, phone numbers, SSNs, cards, IPs and API keys before pasting text into a chatbot, ticket, or log.
- How to Turn a Photo Into Pixel Art (Free, Local) — Pick a block size, snap to a retro palette like GameBoy or Pico-8, and export a clean pixel-art PNG.
- How to use the Pomodoro Technique to focus — Work in focused 25-minute sprints with short breaks — the simple method, plus a calm timer to run it.
- How to Make a QR Code With a Logo in the Center — Add a center logo, gradient, and custom shapes to a QR code that still scans — all in your browser.
- How to Check the Readability Score of Your Text — Get a Flesch reading-ease score, grade level, and long-sentence flags for any text, instantly and offline.
- How to Read and Understand a Regex — Decode any regular expression token by token, with a plain-English explanation and live highlighted matches.
- How to Make a Resume: Free PDF Builder, No Signup — Type your experience, structure it the way recruiters scan, and export a clean one-column resume PDF — privately.
- How to Add Security Headers to Your Website — Build a Content-Security-Policy plus HSTS and clickjacking protection, then copy it straight into nginx or Apache.
- How to create a self-signed certificate — Generate a self-signed cert with SANs for localhost development — no OpenSSL commands required.
- How to audit a sitemap.xml file for SEO errors — Paste your sitemap.xml and find the duplicate, malformed and over-limit URLs that quietly hurt crawling.
- Social Media Character Limits: Check Before You Post — The current character limits for X, LinkedIn, Threads and YouTube — and how to see where each one cuts you off.
- How to Make a Spectrogram of an Audio File — Turn any audio file into a spectrogram and waveform in your browser — read exact Hz, note, and dB.
- How to Format & Beautify a SQL Query — Turn a one-line, unreadable query into clean, indented SQL — with the right dialect rules.
- How to Hide Text in an Image (Free, In-Browser) — Embed a hidden message in an image's pixels — and read it back — entirely on your device.
- How to Sync Subtitles That Are Out of Sync — Fix subtitles that run early, late, or drift over time — a fixed offset or two-point anchor sync, no upload.
- How to Optimize SVG Files in Your Browser — Shrink bloated SVG exports, fix Inkscape and Figma cruft, and copy a clean React component or data URI.
- How to Convert SVG to PNG (or JPG) in Your Browser — Rasterize SVG to PNG, JPG, or WebP at any pixel size — transparent or filled — without uploading a thing.
- How to Use a Teleprompter to Read a Script on Camera — Read your script on camera without losing eye contact — set the speed, mirror it for a beam-splitter rig, go fullscreen.
- How to Compare Two Text Files and Spot Changes — Paste two versions of any text and instantly see what was added, removed, or changed — line, word, or character.
- How to Rewrite Text With AI (Privately) — Rewrite, summarize, fix grammar or change the tone of any text with a local AI model — no signup, nothing uploaded.
- How to Summarize a Long Article Fast (No AI Needed) — Paste any article, doc, or thread and pull out the key sentences in seconds — right in your browser.
- How to Remove Duplicate Lines From Text — Strip duplicate lines, sort, and tidy messy text in seconds — all locally in your browser.
- How to Make a YouTube Thumbnail (Free, No Upload) — Grab a frame or image, add bold text and overlays, preview it inside YouTube, and export 1280×720 — all in your browser.
- How to Schedule a Meeting Across Time Zones — Find a meeting time that works for every city — no time-zone math, no spreadsheets, no guesswork.
- How to Generate a 2FA Code From a Secret Key — Turn a TOTP secret key into a live 6-digit 2FA code in seconds — entirely offline, nothing uploaded.
- How to Convert Units: A Fast, Offline Guide — Convert length, weight, temperature, area, speed, data, and volume instantly — right in your browser.
- How to Add UTM Parameters to a URL — Tag any link with source, medium, and campaign parameters so analytics shows exactly where your traffic came from.
- How to Generate a UUID (v4, v7) or ULID — What UUID v4, v7 and ULID actually mean, when to pick each, and how to generate one or thousands at once.
- How to Take Voice Notes That Summarize Themselves — Talk through a meeting or idea and walk away with a transcript and a tidy summary — no typing, no uploads.